(i) Field of the Invention
This invention relates to gas-emitting bath additive compositions which are stably preserved over a long term.
(ii) Description of the Prior Art
Bath additives are usually made of mixtures of inorganic salts or materials such as Glauber's salt, borax, sulfur, sodium chloride, carbonates and the like, admixed with perfumes, colorants, plant extracts, organic acids and the like. These additives serve to impart agreeable fragrance and color to a hot bath and also to give a proper impetus to skin, thus promoting the circulation of blood and leading to recruitment and promotion of metabolism. Among these bath additives, there are known gas-emitting bath additives comprising combinations of carbonates and organic acids. This type of gas-emitting bath additive allows carbon dioxide gas to be generated or emitted in or throughout a hot bath, producing the effect of permitting one to relax and refresh while enjoying the bath.
However, even though anhydrous carbonates and anhydrous organic acids are used in these gas-emitting bath additives, they are so unstable as to permit reaction therebetween even by presence of a very small amount of moisture or water, causing carbon dioxide to be generated at the time when not required. Accordingly, even when such gas-emitting bath additives are tightly packed in container and preserved over a long term, such a container is expanded by the action of carbon dioxide gas generated. This results in poor appearance of the container and a lowering of commercial value, with the attendant disadvantage that the satisfactory gas-emitting effect cannot be achieved because of a lowering of gas-emitting ability.
In order to overcome the disadvantages, attempts have been made, without practical success, to use moisture absorbents such as anhydrous sodium sulfate, starch and the like.